Track for stairlifts

ABSTRACT

A stairlift includes a rail cross-section and mounting rollers which, in combination, allow a stairlift assembly to be achieved which occupies little space and has a reduced visual impact. The rollers engage rolling surfaces arranged about the outer periphery of a tubular rail. The surfaces are preferably defined by structural components of the rail and are preferably non-parallel and non-perpendicular to the stair surfaces upon which the stairlift is mounted.

FIELD OF THE INVENTION

This invention relates to stair mounted elevators or lifts, commonlyknown as stairlifts.

BACKGROUND

A stairlift, in the form of a carriage mounted for movement along arail, is a well known form of apparatus for moving aged or handicappedpersons up and down a staircase. Such a form of apparatus needs to bedesigned so that the carriage runs smoothly along the rail yet isresistant to forms of movement other than linear movement along therail. Particular movements which need to be resisted are skewing aboutthe rail, which might cause the carriage to jam as it moves along therail; tilting of the carriage about an axis transverse of the railwhich, unless strictly controlled, can cause the carriage seat to moveoff the horizontal and alarm a user; and rotation of the carriage aboutthe rail axis which, again, would have an alarming affect on a user.

The desired smoothness of longitudinal movement, as well as resistanceto unwanted movement, is typically provided by including within thecarriage, spaced pairs of rollers which serve to mount the carriage onthe rail. Generally, the greater the distance between the rollers, themore stable the carriage is on the rail. As a consequence rail designshave tended to be quite broad so that the roller spacings can be as wideas possible. This, in turn, has meant that the resulting stairlift hastended to occupy a considerable margin down one edge of a staircase.

Typical prior art stairlifts have at least six pairs of rollers toprovide the necessary rolling support to the carriage whilst resistingthe undesired movements mentioned above. Obviously the more rollerswhich are included, the greater the cost. However, even with six rollerpairs, some prior art stairlifts still display a degree of uncontrolledmovement in the assembly due to the need to provide clearance betweenopposite sides of the rollers, and the rail.

It is an object of this invention to provide a stairlift which iscompact in nature, includes a minimum number of operating parts andfeels safe and secure to a user; or to provide a form of stairlift whichwill at least provide a useful choice.

SUMMARY OF THE INVENTION

Accordingly, in one aspect, the invention provides stairlift apparatusincluding:

tubular rail having a substantially uniform cross-section and aplurality of rolling surfaces extending longitudinally thereof;

carriage mounted for movement along said rail, said carriage beingarranged to locate a seat section above said rail and having a pluralityof rollers which engage with said rolling surfaces to support saidcarriage on said rail,

said apparatus being characterised in that said rolling surfaces arearranged about the outer surface of a tubular rail of non-cylindricalcross section and said rollers are arranged to support said carriage forrolling movement along said rail yet prevent said carriage from rotationabout said rail.

Preferably the construction and arrangement is such that said rollersand said rail further operate to resist tilting and skewing movement ofsaid carriage with respect to said rail.

Preferably said rail has at least three rolling surfaces arranged aboutthe outer surface of said rail, a roller contacting each of said rollingsurfaces. More preferably said rail includes four rolling surfacesarranged about said cross-section to extend longitudinally of said rail,a pair of longitudinally spaced rollers being provided for each of saidrolling surfaces.

Said rolling surfaces are conveniently provided as an upper pair and asa lower pair and said rail preferably further includes rail mountingmeans defined between said lower pair of rolling surfaces.

The individual rolling surfaces of each pair, and the juxtaposedsurfaces of the different pairs, are preferably perpendicular to eachother and drive transfer means is preferably provided on or adjacent oneof said rolling surfaces. The drive transfer means is preferablyprovided on one of the upper rolling surfaces.

Whilst the drive transfer means could comprise a section of the railadapted for frictional engagement with the carriage, said drive transfermeans preferably comprises a gear rack.

The apparatus as set forth above may further including rack cover meansto at least partially overlie said rack and screen said rack from sightwhen the rail is viewed from above. This rack cover means preferablycomprises a moulding or extrusion fixed above the rack and extendinglongitudinally of the rail.

The apparatus may further include a drive wheel mounted within saidcarriage, the periphery of said drive wheel being engageable with saiddrive transfer means so that, upon rotation of said drive wheel, saidcarriage is moved longitudinally of said rail; and drive means mountedwithin said carriage, said drive means having a drive shaft rotatableabout a drive axis, said drive wheel being mounted for rotation on saiddrive shaft; the arrangement being characterised in that said drivemeans does not overlie said rail when viewed in a directionperpendicular to said drive axis. In such an arrangement, the drivetransfer means preferably comprises a rack and said drive wheelcomprises a pinion which, in use, engages with said rack.

Preferably all of said rollers which support the carriage on the railare identical and the mounting arrangement of the rollers is preferablysuch that each of said rollers is only loaded substantiallyperpendicular to its respective axis of rotation.

The carriage preferably includes a pair of spaced side plates whichextend down to at least partially overlie opposite side parts of saidrail, said rollers extending from said side plates. These side platespreferably comprise outer surface parts of said carriage and may includebracing means on the inner surfaces thereof, said plurality of rollersbeing mounted on said bracing means.

Said side plates and said bracing means are preferably press formed fromsheet metal and subsequently welded together.

In order to allow for adjustment of said carriage on said rail, saidrollers are preferably provided in co-operating pairs, wherein some ofsaid rollers of each pair rotate about fixed axes whilst the axes of theremainder of said rollers in each pair may be displaced in directionsperpendicular to said axes.

In a further aspect the invention provides a stairlift rail having asubstantially uniform tubular cross-section and a plurality of rollingsurfaces extending longitudinally thereof, the rail being characterisedin that said cross section is non-circular and said rolling surfaces arearranged about said cross-section on the outer surface of said rail.

The rail as set forth above preferably further includes a drive surfaceco-planar with, or parallel to, one of said rolling surfaces, and a railmounting plane, wherein said drive surface is arranged at substantially45° to said rail mounting plane.

Preferably said drive surface is constructed and arranged to mount adrive rack.

The rail preferably further includes locating means to receive andlocate joining members, said joining members being operable to join likesections of rail together in end-abutting register. Such locating meanspreferably include a plurality of joining channels formed on the innersurface of said rail, said channels, in use, receiving joining membersin the form of pins.

Said rolling surfaces are preferably provided as a lower pair and anupper pair, each of the surfaces of the upper pair being juxtaposed to asurface of the lower pair but having an apex therebetween and wherein ajoining channel is formed at or adjacent to the inner surface of eachapex.

Said joining channels are preferably substantially circular in sectionso as to receive, by way of interference fit, joining pins of circularsection.

A stairlift rail in accordance with the invention is conveniently formedas an aluminum extrusion.

In still a further aspect the invention provides a stairlift rail foruse in the apparatus hereinbefore set forth.

Many variations in the way the present invention may be performed willpresent themselves to those skilled in the art. The description whichfollows is intended as an illustration only and the absence ofdescription of particular alternatives or variants should in no way beapplied to limit the scope of the invention. Such description ofspecific elements which follows should also be interpreted as includingequivalents whether existing now or in the future. The scope of theinvention should be defined solely by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

One form of stairlift incorporating the various aspects of the inventionwill now be described with reference to the accompanying drawings inwhich:

FIG. 1: Shows a side elevational view of a stairlift carriage embodyingvarious aspects of the invention, the carriage being shown, forconvenience, mounted on a horizontal rail;

FIG. 2: Shows a sectional view, part schematic, through the carriage andrail combination shown in FIG. 1;

FIG. 3: Shows an end elevational view of the carriage shown in FIG. 1with the rail shown in outline only;

FIG. 4: Shows a end sectional view of the carriage and rail combinationshown in FIG. 2 illustrating a roller configuration used to support thecarriage on the rail;

FIG. 5: Shows a further sectional view through the carriage and railassembly, with a number of components omitted for the sake of clarity,and illustrating certain safety devices included in a stairliftembodying the invention;

FIG. 6: Shows a cross sectional view of a rail extrusion used in theassembly shown in FIGS. 1 to 5;

FIG. 7: Shows a cross-sectional view of a rack cover used in theassembly shown in FIGS. 1 to 5;

FIG. 8: Shows an enlarged cross-sectional view of part of the assemblyshown in FIG. 5 but including greater detail of a rack mountingarrangement according to the invention;

FIG. 9: Shows a plan view of part of the detail shown in FIG. 8;

FIG. 10: Shows an end sectional view of a plate arrangement used in amethod of joining rail sections according to the invention;

FIG. 11: Shows a joining pin used in a method of joining rail sectionsaccording to the invention;

FIG. 12: Shows a partial side view of a two rail sections being broughtinto end register, and joined, using the components illustrated in FIGS.10 and 11;

FIG. 13: Shows a side view of a rail hinging mechanism applicable to astairlift according to the invention;

FIG. 14: Shows a view along the line A—A in FIG. 13;

FIG. 15: Shows a view along the line B—B in FIG. 13;

FIG. 16: Shows an enlarged view along the line C—C in FIG. 13;

FIG. 17: Shows an end view through the rail section of FIG. 6 assembledon to a mounting bracket according to the invention;

FIG. 18: Shows a side view of part of the assembly shown in FIG. 17;

FIG. 19: Shows a side elevational view of a chair interface unit mountedon the carriage and rail combination shown in FIG. 1;

FIG. 20: Shows an end sectional view through the rail extrusion shown inFIG. 6 with an electrical junction box, also shown in section, assembledthereon;

FIG. 21: Shows a side elevational view of the assembly shown in FIG. 20;

FIG. 22: Shows a view along the line D—D in FIG. 2;

FIG. 23: Shows a side sectional, schematic view of a rail, a carriageand cable tensioning means, according to the invention, located withinthe rail; and

FIG. 24: Shows a plan view of the tensioning means shown in FIG. 23.

DESCRIPTION OF WORKING EMBODIMENT

The present invention provides a novel configuration of stairliftapparatus which is un-handed; compact, in that it occupies less spaceand has less visual impact than typical prior art stairlifts; and alsoincorporates a reduced number of operating parts with innovativeassembly features in order to function efficiently and safely.

In the form shown in the attached drawings, the stairlift includes acarriage 30 mounted substantially above, for movement along, a tubularrail 31 of constant cross section. Two roller sets 32 and 33 (FIG. 2)support the carriage on the rail, the rail and roller configurationbeing such as to permit smooth movement of the carriage longitudinallyof the rail yet prevent tilting, skewing and rotation of the carriageabout the rail. In the form shown, each of the roller sets 32 and 33comprises four rollers, the set 32 being shown in FIG. 4 and comprisingrollers 32 a, 32 b, 32 c and 32 d. The roller set 33 is identical to theroller set 32 but is spaced along the carriage as is evident from FIG.2.

All rollers of both of the roller sets 32 and 33 are preferablyidentical.

In accordance with conventional practice, the rail 31 has a rollingsurface for the corresponding rollers of the sets 32 and 33, the rollingsurfaces being indicated by reference numerals 34 a, 34 b, 34 c and 34d. As can be seen, the rolling surfaces are arranged about the crosssection of the tubular rail, extend longitudinally of the rail 31 andare formed by the same elements that define the structural elements ofthe tube. This leads to a compact and structurally efficient rail and isin contrast to typical prior art stairlift rails in which the mainsupporting rolling surfaces are typically spaced across the rail, oftensupplemented with vertical surfaces which act as bearing surfaces foranti-skew rollers.

As can be seen, each of the rolling surfaces 34 a, 34 b, 34 c, and 34 dis preferably planar in form and in this form, juxtaposed surfaces areperpendicular. In other words, surfaces 34 a and 34 b and surfaces 34 cand 34 d, are perpendicular. In addition, the planes of surfaces 34 band 34 c, and 34 d and 34 a, are perpendicular in the form shown. Toenhance the compact nature of the rail all the rolling surfaces are,unlike prior art stairlift rails, neither parallel to, or perpendicularto, the rail mounting plane 35 (FIG. 4). In the form shown, all surfacesare at 45° to the mounting plane 35.

As can be seen in FIG. 6, the surfaces may be viewed as being arrangedin upper and lower pairs, the upper pair comprising surfaces 34 b and 34c, and the lower pair comprising surfaces 34 a and 34 d. Situatedbetween the lower surface pair 34 a and 34 d, is a mounting section 36which serves to facilitate mounting of the rail 31 on the stairs of astaircase 37 (FIG. 13), and which may also serve as a mounting base forvarious other components as will be described in greater detail below.

As shown, the mounting section 36 includes a downwardly facing channel38 having inwardly aligned lower flanges 39.

A drive or traction surface is also provided on the rail, preferablyparallel to one of the upper rolling surfaces, in this case the rollingsurface 34 c. It should be appreciated, however, that the drive ortraction surface could be provided in a variety of locations about therail periphery including, for example, on an undersurface of the rail.

Whilst the traction surface could be a surface adapted for frictiondrive, and thus be a co-planar section or extension of surface 34 c, inthis case the surface 34 c includes suitable drive mounting means 40 tomount and retain drive transfer means 41, which drive transfer meanspreferably comprises a rack.

Referring now to FIG. 8, in the embodiment herein described, the drivemounting means 40 comprises a further channel defined in part byinwardly aligned arms 42 having an access slot 43 therebetween. Thechannel 40 is sized and configured to slidably receive and retain aplurality of fixing bases preferably in the form of captive nuts 44although these nuts 44 could be replaced by one or more tapped stripswhich slide into the channel 40. The rack 41 is sized to overlie theaccess slot 43 and bear on outer surface parts of the arms 42. Fixingmeans, preferably in the form of machine screws 45, are then passedthrough countersunk holes 46 formed through the rack 41, passed throughthe access slot 43 to engage in the captive nuts 44. It will beappreciated that as the screws 45 are tightened in the nuts 44, the rackis drawn down against outer surface parts of the arms 42 whilst the nutsare drawn up against inner surface parts of the arms 42 thus clampingthe rack firmly in position.

This arrangement allows the mounting holes 46 to be preformed in therack and for the rack to be readily mounted in position quickly andaccurately, and easily removed and replaced if necessary.

It is envisaged that the rail could be provided with a further channelin rolling surface 34 b, the further channel being identical in form tochannel 40 and being positioned on surface 34 b so as to be a mirrorimage of channel 40 about the central vertical axis of the rail. In sucha form the rail could be “handed” by the installer, on site.

Referring now to FIG. 9, the rack 41 is further secured at each endthereof by fixing plates 47, one of which is shown in FIG. 9. As can beseen the plate is fixed to surface part 34 c by machine screws 48 or thelike, so as to stand proud of the surface part 34 c, and includes a step49 which engages the end of the rack and thus prevents any movement ofthe rack 41 to the left as shown in FIG. 9. An identical plate (notshown) fixed at the opposite end of the rack 41 prevents movement in theopposite direction. The plates 47 further serve as mechanical safetystops for the carriage as it approaches the ends of the rail in a mannerwhich will be described in greater detail below.

The rail preferably further includes some means to at least partiallycover the rack when the apparatus is viewed from above so as to reducethe possibility of interference with the rack and, hopefully, to enhancethe aesthetic appearance of the apparatus. Whilst this cover means couldbe formed integrally with the rail 31, in the form shown a separate rackcover or masking member 50 (FIG. 7) is provided, preferably in the formof a plastics moulding or extrusion. As can be seen, the member 50 has acovering arm 51 which provides the covering or masking function, and afixing base 52 which serves to fix the member 50 on to the rail 31. Inthe form shown, both edges of the base 52 curve down into side margins53 a, 53 b each of which has a fixing lip 54 defined on the lower inneredge thereof. The lips 54 are configured to clip into grooves 55 formedon an upper part of the rail 31 between the rolling surfaces 34 b and 34c. Finally, the cover member 50 preferably further includes a pair ofupwardly aligned ribs 56 extending along the upper surface thereof, thepurpose of which will become apparent later in this description.

It will be appreciated from FIGS. 4 and 5 that, when the cover member 50is fixed in position on the rail 31, not only is the rack 41 largelyhidden from view from above, but also a decorative effect is provided tothe upper part of the rail.

The rail section as above described is conveniently extruded fromaluminum. Suitable grades of aluminum include 6063, hardness T6. Therail may be left in its natural, as extruded, form, or may be painted oranodised. Alternatively, the rail could be pultruded in a variety ofmaterials, both metallic and non-metallic (or combinations of metallicand non-metallic) or the rail could even be fabricated from sections ofplate material. In many stairlift applications it is necessary to joinsections of rail end-to-end in order to increase the effective length ofthe rail. The present invention partly accommodates this need byproviding the rail extrusion with internal joining means which, when twolike sections of rail are brought into end-to-end register, can becombined to form a joint between the sections. Referring now to FIGS. 10to 12, the joining means includes a pair of joining channels 58, formedso as to extend along the inner surface of the rail 31, the channels 58receiving and retaining joining pins 60. The joining pins 60 areselected or formed to be an interference fit within the channels 58 andare first located in a first one of the rail sections so that, as shownin FIG. 12, parts thereof project out from the first rail section. Thesecond rail section is then aligned with the first section, and movedtoward the first section so that the projecting parts of the pins 60engage in the channels 58 of the second rail section.

As can be seen in FIG. 11, each pin 60 is preferably knurled over part59 of the outer surface thereof. When each pin is inserted into achannel 58 of the first rail section, it is so inserted until at leastpart, and preferably substantially all, of the knurled section 59 islocated in the channel 58 of the first section. The knurling 59 servesto firmly retain the pins in the channels 58.

Whilst the channels 58 could be located at any points on the innerperiphery of the rail 31, the same are preferably located at the innerjunctions between the juxtaposed pairs of rolling surfaces 34 a, 34 band 34 c, 34 d. In this way, any joint along the rolling surfaces issecurely aligned and firmly braced by the joining pins and thusovercomes the problem, experienced with prior art rail joints, inadjacent sections of rolling surface being slightly mis-aligned, thuscausing some bumping as the carriage rides over the joint.

The rail joint as described above is preferably braced by outer bracingplates 62 which span the joint. In the form shown the bracing plates 62are fixed to inner mounting plates 63 located within the mountingchannel 38 provided on the lower edge of the rail 31. Machine screws 64are used to fix the plates 62 to the plates 63.

The channels 58 may serve a further function. At the rail ends, covers(not shown) are typically provided to close off the ends of theextrusion. These covers may be fixed into position by fasteners (notshown) which pass through the covers and engage in the channel 58.Whilst the fasteners could be self-tapping, for this applicationthreaded inserts are preferably inserted in the channels 58.

As described above, the mounting channel 38 serves as a location formounting means used to mount the rail 31 in a staircase. Referring nowto FIGS. 17 and 18, the mounting means may comprise a plurality of likebrackets 66, each comprising a rail engaging part 67 and a stairengaging part 68. As can be seen from FIG. 17, the rail engaging part 67is engaged to the rail 31 through a single lock bolt 70 engaging in lockplate 69 fixed within channel 38. The arrangement is such that, prior tobeing locked, the bolt 70 defines a pivot aligned with the centralvertical axis 72 of the rail. This allows the bracket 66 to be pivotedabout the axis 72 before the bolt 70 is locked. With the lock bolt 70slackened, the lock plate 69, and thus the bracket 66, can be positionedat any point along the rail and the bracket can be rotated about axis72. When all components have been aligned to the installer'ssatisfaction, the lock bolt 70 is tightened, thus locking the componentsin position.

To prevent deformation of the rail engagement part 67, the edges of thecentre part thereof are turned down to provide strengthening flanges 73.In addition, the risk of the rail engagement part deforming may befurther reduced by press forming the centre section of part 67 to a bellshape, which bell shape projects through the space between lower channelflanges 39 and engages the lower surface of lock plate 69.

The assembly of the rail on a mounting bracket is shown in a horizontalposition in FIG. 17, this being an unlikely configuration for astairlift rail. A more realistic arrangement is shown in FIG. 18 inwhich the rail 11 is at angle Ø to a horizontal plane 75. The plane 75is typically represented by a stair tread and we have found, in thepast, that there can be considerable horizontal misalignment of stairtreads, including mis-alignment across the stair treads. The use of thesingle central pivot mount described herein allows us to easilyaccommodate a degree of cross-wise slanting of stair treads as, when therail is sloped as shown in FIG. 18, pivoting of the bracket 66 aboutpivot bolt 70 raises and lowers contact feet 76 a and 76 b, formed asthe lower parts of stair engaging section 68, with respect to oneanother.

As can be seen, the two parts 67 and 68 are pivoted together alongfurther pivot axis 78 which is orthogonal to axis 72 and allows thebrackets to accommodate different rail gradients (differences in angleØ) as well as a degree of different gradient on the various stairtreads.

In some stairlift applications it is necessary or desirable to hinge endsections of the stairlift rail with respect to the main, central part ofthe rail. Such arrangements are well known in prior art stairliftinstallations, however, the present invention advances the art byproviding not only a simplified form of hinge but also providing asimple yet effective means of mounting the hinge.

Referring now to FIGS. 13 to 16, a hinge mechanism 80 is shown betweenrail section 81 fixed to the staircase 37, and hinged rail section 82.Whilst the hinge mechanism could be manual in operation, in the formshown the mechanism 80 includes a motor 83 driving a right-angle drivegearbox 84. The motor and gearbox combination is preferably arrangedalong the rail axis and is conveniently suspended below the fixed railpart 81, being mounted in the fixing channel 38 by suitable fixing bolts(not shown) engaging in captive fixing plates 79 slidable along butlockable within the channel 38. Being mounted in this way, the positionof the motor 83 and gearbox 84 can be readily adjusted along the railpart 81, and any misalignment readily eliminated.

With the motor and gearbox being aligned along the rail axis, the outputshaft 85 of the right angle drive gearbox lies across the rail andconveniently defines the hinge axis. Thus arms 86 which project from thehinged rail section 82 can be mounted directly on the output shaft 85.

It will be noted from FIG. 15 that the output shaft 85 emerges from bothsides of the gearbox 84 and thus a pair of spaced arms 86 can beprovided as a link to the hinged rail section 82.

A mounting bracket 88 is provided on the underside of the hinged section82 to link the outer ends of arms 86 and to ensure alignment of the railsections as the hinged section 82 is pivoted down into end alignmentwith the fixed rail section 81. As can be seen, the bracket 88 is alsofixed to the hinged rail section 82 by way of channel 38.

In order to balance the reverse torque imposed on the gearbox 84 by themass of the hinged section 82, balancing means are preferably provided.In the form shown, this comprises a spring, preferably a gas spring 90.By adding the gas spring 90 a lower powered motor can be used to providethe requisite hinging action.

Suitable support bracing is preferably provided to the mating ends ofthe rail parts to minimize deformation of the rail parts as the ladencarriage travels over the hinge joint. This support bracing can be seenmost clearly in FIG. 16 and, in the form shown, comprises an innerbracing channel support 92 which overlies the hinge line and is fixed tothe upper inner surface of the fixed rail part. A supplementary bar part93 may be provided to occupy the cavity formed between the upper part ofthe support 92 and the inner, upper central surface part of the railsection.

The support bracing may further include an external channel member 94,again overlying the hinge line, which surrounds the lower parts of thetwo rail sections, when aligned, and prevents outward deformation ofthose sections when under load. Once again, the channel member 94 issecured to the fixed rail section by bolts (not shown) engaging insuitable fixings (not shown) mounted in the channel 38.

Turning now to a more detailed consideration of the carriage 30, andreferring more particularly to FIGS. 4 and 5, the form of carriagedepicted includes a main chassis 100 which, when the carriage is mountedin position on the rail 31, spans over the rail. Mounted at spacedpoints on the chassis 100, preferably along opposite edges of thechassis, are side plates 101 a and 101 b which extend down to overlie atleast part of both sides of the rail 31. As will be described in greaterdetail below, the side plates also serve as mountings for the individualrollers of the roller sets 32 and 33.

Included on the chassis 100 is a mounting base 102 which is angled tothe remainder of the base and serves as a mounting surface for maindrive motor 104 and gearbox 105. The mounting base 102 may be formedintegrally with the forming process for the chassis i.e. may be pressformed when the chassis is press formed, or may be fixed by welding orbolting to the chassis 100. The chassis 100 also includes a centralaperture 106. This gives clearance to enable drive pinion 108, mountedon output shaft 107 of gearbox 105, to engage with drive rack 41 locatedbelow the chassis 100 on rail 31.

The lower parts of each of the side plates 101 a and 101 b arepreferably provided with internal triangulated bracing members 110 a and110 b respectively, the bracing members extending along the carriage andadding considerable stiffness to that section of the carriage whichprovides the mount to the rail 31. The bracing members also provideconvenient mounting points for the rollers of rollers sets 32 and 33.Indeed, the configuration of bracing which provides significant naturalstrength—a triangle—also perfectly positions the rollers 32 and 33 toengage the perpendicular rolling surfaces of the rail 31. This all helpsto ensure that a compact, yet stable, carriage configuration results.

The carriage is preferably further braced in the vicinity of the rollermounts by folding the centre parts of the side plates 101 a and 101 baround to form fixed centre end cover parts 103 a and 103 b (shown indotted outline in FIG. 3). The end cover parts 103 a and 103 b are, inturn, fixed to the chassis 100.

The bracing members 110 a, 110 b include threaded bosses to receive axlepins 112 and sleeves 113 which mount each of the rollers 32, 33. Thesleeves 113 which mount the top rollers 32 b, 33 b and 32 c, 33 c arepreferably provided with concentric through bores whilst those whichmount the lower rollers 32 a, 33 a and 32 d, 33 d are preferablyprovided with eccentric through bores. This allows the axes of therollers 32 a, 33 a and 32 d, 33 d to be adjusted toward and away fromthe rolling surfaces 34 a and 34 d respectively, and thereby allow anyslack between the carriage and the rail, to be easily and effectivelytaken up. As an alternative, the axes of the rear roller sets 32 c, 33 cand 32 d, 33 d could be fixed whilst those of the front sets 32 a, 33 aand 32 b, 33 b could be provided on eccentrics so as to provide thenecessary adjustment.

It will be appreciated, when viewing the arrangement shown in FIG. 4,that all the rollers 32, 33 are in positive engagement with the rail atall times, thus ensuring smooth travel of the carriage longitudinally ofthe rail whilst preventing tilting, skewing or rotation of the carriageabout the rail. Further, this secure and smooth form of motion can beachieved using two sets of four identical rollers rather than the six,often varied, sets of rollers typically found in prior art stairlifts.

The rollers 32, 33 may be formed from any suitable material, one examplebeing nylon which is preferably impregnated with molybdenum sulphide.

With the drive transfer means 41 being in the form of a rack, the drivewheel 108 comprises a compatible pinion. However, it will be appreciatedthat the drive transfer means could comprise a simple surface, perhapspatterned or roughened, and the wheel 108 a simple wheel arranged tofrictionally engage the transfer surface.

With the arrangement shown, the motor 104 and gearbox 105 are spacedaway from the rail and, when viewed in a direction perpendicular to theaxis of output shaft 107, the motor and gearbox combination do notoverlie the rail 11. This allows the gearing of the stairlift to besimply varied by varying the diameter of the wheel 108 and providingvarying thickness packing between the gearbox 105 and mounting base 102,this being possible without encountering problems of the motor/gearboxfouling on the rail. Alternatively, the rack 41 could be packed upwardlyto correctly engage a smaller diameter pinion 108.

In particular, the arrangement depicted and described permits the use ofsmall, standard size pinions to be used in combination with a relativelyinexpensive single stage gearbox rather than the more expensive stepdown gearboxes typically used heretofore.

It will also be seen that the pinion 108 engages rack 41 which islocated on one of the upper rolling surfaces 34 c whilst the gearboxsubstantially overlies, but is spaced from, the other upper rollingsurface 34 b. Thus the mass of the carriage is relatively evenlyarranged about the central axis 72 of the rail, which assists theoverall stability of the stairlift.

It will also be seen that the side plates 101 a and 101 b alsopreferably comprise part of the outer surface of the carriage. A furthercross member 115 may, as shown, be provided which projects between upperparts of the side plates 101 to stiffen the carriage and serve as amount for other components as will be described in greater detail below.

The chassis 100, side plates 101, bracing members 110 and cross member115 are preferably all press formed from sheet metal, and are thenlocated in a jig, and spot welded together. This considerably simplifiesfabrication of the carriage and enables a lighter structure to achievedesired strength parameters.

The carriage 30 also includes a novel arrangement for mounting astairlift chair (not shown) on the carriage. As can be seen in FIG. 19,chair interface unit 120 is mounted on the carriage 30, the interfaceunit 120 having downwardly extending side members 122 which at leastpartly overlie the side plates 101 a and 101 b of the carriage 30. Acentral mounting hole 124 in each of the side members 122 is alignedwith one of mounting bosses 125 a, 125 b and 125 c (FIG. 1) fixed in theside plates 101 of the carriage. A mounting bolt 126 is then passedthrough the aligned hole, and engaged in the selected boss, to providepivotal support for the interface unit, and thus the chair. After thechair cushion (not shown), mounted on the upper surface 128 of theinterface unit, has been set to the desired angle, a locking bolt 130 ispassed through one of the arcuate slots 132, in the interface unit,which has a locking aperture 134, in side plate 101, exposed thereunder,and is engaged in the aperture 134 and tightened to fix the chair inposition.

It will be noted that interface unit 120 also serves as a mounting pointfor footrest 136.

The provision of a series of mounting bosses 125, and correspondinglocking apertures 134, provides further benefit in that the interfaceunit 120, and thus the chair, may be offset with respect to thecarriage. This, in turn, allows additional clearance to be achieved,when required, at one end of the stairlift and minimises or eliminatesthe problem of rail overhang.

Official regulations or standards require that stairlift installationsinclude various safety features to minimise accidental harm to users ofthe installation or to persons who may come into contact with thestairlift during operation. One requirement is that the stairliftcarriage be brought to a halt, without manual intervention, when itreaches the ends of the rail. This is to ensure that the carriage is notinadvertently powered off the rail. Another requirement is that thecarriage be brought to a halt in the event the carriage encounters anobstacle in its path whilst travelling along the rail.

Various switch configurations have been used in the past, of varyingdegrees of complexity and reliability. The present invention proposesseveral novel features which are believed to provide relatively simpleyet effective and reliable switch operation.

Referring to FIGS. 1, 2 and 5, the end stop switching is provided by abank of three stop switches, a first switch 140, second switch 141 andthird switch 142, the bank of switches being mounted on the lower innersurface of side plate 101 a and being positioned so that the centreswitch 141 lies on, or very close to, the vertical geometric centre ofthe carriage when the carriage is viewed in the position shown in FIG.2. Switch operating means 145 a, 145 b are mounted at or adjacent eachend of the rail. As the carriage arrives at the end to the left in FIG.1, the switch 140 contacts the switch operating member 145 a and cutspower to the motor 104. Should the switch 140 fail to operate, thecarriage continues until ultimate or back-up switch 141 engages themember 145 a and cuts power to all electrical components in thecarriage.

When the carriage is moving in the opposite direction, switch 142 firstcontacts switch operating member 145 b. If switch 142 fails to operatethen ultimate or back-up switch 141 is again brought into play, but thistime through contact with member 145 b.

All three switches 140, 141 and 142 are preferably identical.

There is a further advantage arising from the nature of the switchoperation members 145. The members 145 a at both ends of the rail arepreferably identical and are conveniently mounted using mounting channel38. In the embodiment shown, the members 145 are locked into positionsby locking bolts 146 acting in captive nuts 147 slidable within thechannel 38. In this way, the safety stopping positions at either end ofthe rail can be easily adjusted and reliably fixed.

A further safety back-up is provided to supplement the switches 140, 141and 142. In the event the back-up switch 142 also fails to cut power tothe drive motor 104, the structure of the carriage is designed to foulon rack retaining member 47 which acts as a mechanical barrier tofurther movement of the carriage.

According to a further aspect of the present invention, it is alsoproposed to provide a simple yet effective form of safety cut-out tostop the carriage 30 in the event the carriage encounters an obstacle inits path intermediate the rail ends.

As with prior art devices the carriage 30 includes hinged means which,in the form shown, comprise flaps 150 a and 150 b mounted on oppositeends of the carriage 30, the flaps 150 being preferably folded or pressformed from single section s of sheet metal. As can be seen from FIGS. 1to 3, the flaps have lower sections 151 which extend down to lie onopposite sides of the rail 31. Springs 152 acting between the flaps 150and the carriage ends bias the flaps away from the carriage ends.

The upper part of each flap 150 a, 150 b has an inwardly turned lip 153which engages over the upper edges of carriage end parts 103 a, 103 b toprovide a pivotal mount for each flap.

Each flap further includes side flanges 154 which are formed with hookedkeepers 155. The keepers 155 are configured to engage over the loweredges of slots 156 a and 156 b formed in the carriage end parts 103 aand 103 b to thus limit the displacement of the flaps by the springs152. The flaps 150 are held down in position over carriage end parts 103by upper cover sections 158 a and 158 b, the upper cover sectionsfurther contributing to the enclosure of the interior of the carriage30.

Thus the components combine to provide a simple reliable form of hingeusing the least number of components. Further, it will be noted that thecut-out switches 160 a and 160 b, operated respectively by flaps 150 aand 150 b, require no separate operating linkages, the switches actingdirectly on ramps 161 a and 161 b forming part of the reverse side ofthe keepers 155.

It will be appreciated that as a flap 150 a, 150 b encounters anobstruction in the path of the carriage, the flap is deflected againstthe bias of spring 152 and operates the respective cutout switch 160 a,160 b which brings the carriage to a halt.

Turning now to FIGS. 1, 2 and 22 to 24, in the form of apparatusdepicted and described herein, motor 104 is a DC motor which receiveselectric energy from batteries 165 mounted in the upper part of thecarriage 30. The batteries are preferably charged, continuouslythroughout each operating cycle, from a trailing cable 167, the cable167 being controlled in a manner which will be described in greaterdetail below.

Obviously, the motor 104 could, instead, be an AC motor receiving ACpower via the trailing cable 167.

As shown, the batteries 165 rest under their own weight on lower supportmember 166, the lower support member 166 extending between side plates101 a and 101 b but below cross member 115. The cross member 115 ispreferably of tray-like form and conveniently serves as a mount for muchof the electronics included in the carriage 30. To this end circuitboard 168, which provides the main electrical control function for thestairlift, is mounted on cross member 115. As can be seen, the crossmember 115 also includes a rectangular aperture 170 which, incombination with lower support member 166, defines a bay to securelylocate the batteries 165. The aperture 170 is sized so that, when seatedwithin the bay, the batteries are restrained against substantial lateralmovement.

Electrical cables connecting the various safety cut-out switches and thecircuit board 168 are formed into the arms of a loom, parts 172 of theloom being held into the sides of the battery bay by interaction betweenthe batteries and the bay or, more particularly, between the batteries165 and the cross member 115. To this end, the perimeter of aperture 170in the cross member is provided with notches 174 into which the loomparts are first located and then trapped by the presence of thebatteries 165. This simple feature allows the loom parts 172 to besecurely located in position whilst avoiding the need for cable ties orthe like.

The batteries 165 are restrained against upward vertical displacement bya restraining member 176 which spans across the batteries and engagesthe cross member on opposite sides of the batteries. As can be seen fromFIG. 2, one side of the restraining member includes a lip 177 which,prior to the insertion of batteries 18, is engaged under one edgedefining aperture 170. Once the batteries 165 are in position, the lip177 is prevented from disengagement with the aperture edge. The otherend of the retaining member is formed into a fixing flange 178 which isheld in position by a single fastener 180 which screws into the crossmember 115.

The restraining member 176 is preferably stamped or otherwise formedfrom metal sheet.

In this way a simple, single piece battery restraint is provided whichrequires only one fastener to be fixed in place.

The assembly and reliability of the electrical systems is furtherenhanced by selecting switches of common form and arranging theseswitches into a sub-assembly for the manufacturing process.

As stated above, switches 140, 141 and 142 are preferably identical inform. Switches 160 a and 160 b are also preferably of the same form andidentical to the switches 140 to 142. As can be seen from FIG. 5, allswitches are mounted on the one of the side plates 101, thus allowingthe side plate to be pre-wired before final assembly of the carriage.This simplifies the assembly process. In the form shown, the switchesare mounted on the outer side plate 101 a i.e. the side plate facingaway from the wall when the stairlift is mounted in its operatingposition. This simplifies servicing and replacement of the switch gear.

To allow the pre-wiring to be successfully incorporated, the chassis 100is provided with a slot (not shown) in the edge thereof which mates withside plate 101 a. This slot accommodates the loom when the pre-wiredside plate 101 a is offered up to the chassis.

As mentioned above, the batteries 165 are preferably charged on acontinuous basis throughout all operating cycles of the apparatus, bymeans of a trailing cable 167 permanently wired into an external powersource. A charger (not shown) is obviously wired into the supply circuitand may be located in the carriage or external to the apparatus and mostlikely, conveniently close to the external power source. Typical priorart DC powered stairlifts have charging ramps at opposite end of therail. This means that the batteries are only charged when the carriageis in position at an end of the rail. Further, the ramps are subject towear and tear, and mis-alignment, which often results in the chargingfunction failing and the batteries running out of charge. The trailingcable arrangement means that the batteries are charged at all times.

This invention also proposes a novel form of mechanism for controllingthe trailing cable 167.

It is known to provide a trailing cable arrangement in which a powercable extends out the front face of the carriage adjacent the rail uppersurface, passes around a pulley fixed adjacent the upper end of therail, is engaged with a weighted trolley which can travel inside therail and is then connected to an external source of electrical power.The cable must be of sufficient length to ensure power supply when thecarriage is at the bottom of the rail. The trolley functions to drawexcess cable into the rail interior as the carriage moves up the rail.

Referring now to FIGS. 23 and 24, a novel form of trolley 180 is shownhaving a weighted rectangular body part 181 supported in the interior ofthe rail 31 on a pair of spaced rollers 182. As can be seen in greaterdetail in FIG. 6, the rail has an upper channel 184 and lower upstandingribs 186 which serve to locate the rollers laterally.

The rollers 182 are both preferably identical and are of a diameterwhich is accommodated, with little clearance in the vertical innersection of the rail.

The trolley body 181 is formed from a heavy material such as solid ironor lead so that the trolley is always biased, under its own weight,towards the lower end of the rail and thus maintains tension on thecable 167. The body 181 has forked sections 188 fixed to opposite endsthereof to receive the rollers 182 mounted on axles 187.

The novelty of the present arrangement resides in the fact that at leastthe leading roller 182, and preferably both rollers, have their rollingperipheries shaped to accommodate the trailing cable 167. Thus, thecable 167 is lead from the carriage, directed about pulley 189 mountedat the upper end of the rail in bracket 190, fed around leading roller182 of the trolley, and then lead out and engaged with the externalpower source. Between the carriage and the pulley, the cable 167 may bepartly located by the ribs 56 extending along the upper surface of therack cover member 50.

Pulley 190 is preferably enclosed within end cap 191. Both the bracket190 and the cover 191 are fixed to the rail by fasteners (not shown)engaging in threaded inserts (not shown) fixed in channels 58.

It will thus be seen that the rollers 182 both locate the cable andsupport the trolley, reducing the complexity of the apparatus andreducing cost and assembly requirements. Further, the same trolley canbe used in right and left handed installations without modification.

That end of the cable 167 not connected to the carriage 30 is preferablyconnected to a junction box mounted on the rail but in a position whichdoes not interfere with movement of the carriage along the rail.

Referring now to FIGS. 20 and 21, terminal box 194 is provided which, aswith a number of the components described above, is conveniently mountedon the underside of rail 30, through the fixing channel 38. To this endmounting studs 196, projecting from fixing plate 198 slidable in thechannel 38, are passed through the base of the terminal box and nutsapplied to fix the box 194 in position. A plurality of knock-outapertures 200 are provided in the walls of the terminal box to allow thecables 195 (FIG. 4) which control the various different functions of thestairlift, to pass into the box and be engaged with terminal blocks 202located inside the box. As is evident form FIG. 4, cables needing to runthe length of the rail can be located within the channel 38.

Where cables pass through knock-outs 200, cable glands (not shown) areprovided to prevent cables being abraded by the edges of apertures 200.

It will thus be appreciated that the present invention, at least inrespect of the preferred embodiment described herein, provides a compactform of stairlift apparatus which incorporates a number of innovationsto ensure the provision of a strong, efficient and safe form ofstairlift from a reduced number of working parts.

What is claimed is:
 1. A stairlift apparatus, comprising: a rail meansconsisting of only a single rail, said single rail having asubstantially uniform, non-circular, tubular cross-section; a pluralityof rolling surfaces extending longitudinally from said single rail, saidplurality of rolling surfaces being arranged about said cross-section ofsaid single rail; a drive surface included on one of said plurality ofrolling surfaces; a seat section; and, a carriage mounted for movementalong said single rail, said carriage being arranged for locating saidseat section above said single rail and having a plurality of rollersfor engaging said plurality of rolling surfaces for supporting saidcarriage on said single rail and preventing said carriage from rotatingabout said single rail, said carriage further including a drive wheeldrivingly engaging said drive surface, said plurality of rollers beingmounted for rotating about an axis parallel to one rolling surface ofsaid plurality of rolling surfaces which a given roller of saidplurality of rollers engages, and said drive wheel being mounted forrotating about an axis parallel to a plane of a given rolling surface ofsaid plurality of rolling surfaces on which said drive surface isincluded.
 2. The stairlift apparatus according to claim 1, furthercomprising means for minimizing tilting and skewing movement of saidcarriage relative to said single rail.
 3. The stairlift apparatusaccording to claim 1, wherein said single rail includes at least threerolling surfaces about an outer surface of said single rail, with oneroller of said plurality of rollers contacting each of said threerolling surfaces.
 4. The stairlift apparatus according to claim 1,wherein said single rail includes four rolling surfaces about saidcross-section of said single rail extending longitudinally of saidsingle rail, a longitudinally spaced pair of rollers of said pluralityof rollers being provided for each of said four rolling surfaces.
 5. Thestairlift apparatus according to claim 4, where in said four rollingsurfaces are provided as a pair of upper rolling surfaces and a pair oflower rolling surfaces.
 6. The stairlift apparatus according to claim 5,wherein said single rail further includes means for mounting said singlerail between said lower pair of rolling surfaces.
 7. The stairliftapparatus according to claim 5, wherein said rolling surfaces of saidpair of upper rolling surfaces and said pair of lower rolling surfacesare juxtaposed surfaces of different pairs of said pair of upper rollingsurfaces and said pair of lower rolling surfaces.
 8. The stairliftapparatus according to claim 7, wherein said juxtaposed surfaces ofdifferent pairs of said pair of upper rolling surfaces and said pair oflower rolling surfaces are perpendicular to one another.
 9. Thestairlift apparatus according to claim 5, further comprising drivetransfer means on, or adjacent to, one pair of said pair of upperrolling surfaces.
 10. The stairlift apparatus according to claim 9,wherein said drive transfer means comprises a gear rack.
 11. Thestairlift apparatus according to claim 10, further comprising rack covermeans for at least partially overlie said gear rack and a screen fromsight when said single rail is viewed from above.
 12. The stairliftapparatus according to claim 11, wherein said rack cover means comprisesa mounding or extrusion fixed above said gear rack and extendinglongitudinally of said single rail.
 13. The stairlift apparatusaccording to claim 1, further comprising: drive means mounted withinsaid carriage, said drive means having a drive shaft rotatable about adrive axis, with said drive wheel being mounted for rotation on saiddrive shaft, said drive means not overlying said single rail when viewedin a direction perpendicular to said drive axis.
 14. The stairliftapparatus according to claim 13, wherein said drive surface comprises arack and said drive wheel comprises a pinion engagable with said rack.15. The stairlift apparatus according to claim 1, wherein all rollers ofsaid plurality of rollers are identical.
 16. The stairlift apparatusaccording to claim 1, wherein each roller of said plurality of rollersis only loaded substantially perpendicular to its respective axis ofrotation.
 17. The stairlift apparatus to according to claim 1, whereinsaid carriage has a pair of spaced side plates extending downwardly toat least partially overlie opposite side parts of said single rail, saidrollers extending from said pair of spaced side plates.
 18. Thestairlift apparatus according to claim 17, wherein said pair of spacedside plates comprise outer surface parts of said carriage.
 19. Thestairlift apparatus according to claim 17, wherein said pair of spacedside plates include bracing means on inner surfaces thereof, saidplurality of rollers being mounted on said bracing means.
 20. Thestairlift apparatus according to claim 19, wherein said pair of spacedside plates and said bracing means are press formed from sheet metal andsubsequently welded together.
 21. The stairlift apparatus according toclaim 1, wherein said plurality of rollers are provided in cooperatingpairs wherein some of said plurality of rollers of each pair of rollersrotate about fixed axes while axes of remaining rollers of saidplurality of rollers in each said pair of rollers are displaceable indirections perpendicular to said axes.
 22. The stairlift apparatusaccording to claim 1, wherein said drive surface is arranged atsubstantially 45° relative to a rail mounting plane.
 23. The stairliftapparatus according to claim 1, further comprising joining members andmeans for receiving and locating said joining members, said joiningmembers being operable for joining sections of rail of said single railtogether in an end-abutting register.
 24. The stairlift apparatusaccording to claim 23, wherein said means for receiving and locatinginclude a plurality of joining channels formed on an inner surface ofsaid single rail, said plurality of joining channels being capable ofreceiving joining members formed as pins.
 25. The stairlift apparatusaccording to claim 24, wherein said plurality of rolling surfaces areprovided as a lower pair of rolling surfaces and an upper pair ofrolling surfaces each rolling surface of said of upper pair of rollingsurfaces being juxtaposed to a surface of said slower pair of rollingsurfaces, but having an apex therebetween and with a joining channelformed at, or adjacent to, an inner surface of each said apex.
 26. Thestairlift apparatus according to claim 25, each joining channel of saidplurality of joiniing channels is substantially cylindrical forreceiving and joining pins of circular section via an interference fit.27. The stairlift apparatus according to claim 26, wherein saidplurality of joining channels are positioned for receiving fixing screwsused in a mounting of end caps and trailing cable tensioning means. 28.The stairlift apparatus according to claim 27, wherein said single railcomprises an aluminum extrusion.